Two AA batteries required, batteries sold separately
by Xmarksthespot
Summary: In which Molly and Sherock know they're soulmates, and everything is still the same. Well, almost everything. (Because Molly is still too kind and giving and Sherlock sometimes needs the high that coffee and nicotine won't give). — Soulmate!AU, Sherlock&Molly


**Title**: Two AA batteries required. Batteries sold separately.  
**By**: Xmarksthespot  
**Disclaimer**: I don't own any rights to the copyrighted material.  
**Notes**: Pretty much a two year project considering this is the dozenth soulmate AU attempt I've made with Sherlolly. Crossposted on AO3, but someone had asked for this to be posted here too, so here you go! :)

* * *

Molly Hooper thinks, three months into meeting the infamous Sherlock Holmes, this is what it would be like to be high on ecstasy, with a string on her back pulling her up high as the coffee cup slips from both his and her grips. His black with two sugars splatters on the ugly flooring below them, a slosh of liquid staining both their shoes, but Molly's too awe-struck to even notice with her mouth hanging wide. Sherlock, for once, seems entranced at a living body. _Hers_.

"I…" she starts, because her high has finally come down. She thinks Sherlock's has too, but she has a nasty habit of speaking before she carefully thinks through, so when she opens her mouth, about to tell him that she had never truly believed in soulmates before, how rare it was, but she thinks _this_ will work, Sherlock grabs onto her forearm and an electric pulse runs through their bodies again.

He keeps his hold on her long enough for the initial wave of pleasure to die down, enough that she's aware of the rush of blood pumping through her veins. She's read textbooks on this before. It was mandatory in medical school, how sometimes soulmates are present during surgeries, just holding their loved one's limp hands, how the evolution of mankind has led to symbiotic mutualism, allowing humans to give a little, take a little, in more ways than one. Molly can feel the long hours of work shorten in her mind, her eyelids feel less heavy. Her skin beneath Sherlock's fingers release waves of energy and pleasure throughout her body. She dares call it a mini-orgasm.

His grip on her lightens, and then disappears altogether, surprising Molly. Sherlock drops his arm, and he folds it behind his back. Molly knows he's analyzing what had just happened, and she realizes how bad she has it. Three months into meeting Sherlock, and she already knows his facial expressions. But, she thinks, it will be okay, because at least they were meant to be together, that her crush on him since day one had never been silly.

"Hm," Sherlock hums, snapping Molly out of her thoughts. He then steps over the puddle of coffee, walking passed her and mutters an "interesting", before going back to his work.

Molly looks over her shoulder, at the cold man who decidedly not to acknowledge their revelation. Three months into meeting Sherlock Holmes, her soulmate, Molly tucks away the memory of her stomach dropping and the stinging sensation at the corner of her eyes. It's for later use, she thinks, to remind herself, just as she lists off the negative side effects of ecstasy. Drugs leads to crashes, and Sherlock Holmes will always be a terrible withdrawal.

* * *

She doesn't tell anyone about her connection with Sherlock, not even to her best friends. How embarrassing would it be to admit that she's found her soulmate, only to be rejected for a decapitated corpse. Her memory of Sherlock walking away from her sticks longer than her memory of the euphoria anyway, and the statistics roll around in her head that not too many people find their soulmates, what with the world being so big. It doesn't help her massive crush on him though, which grows every time he shows up in her lab.

It's strange for Molly. She can quite easily separate her feelings for him and the hidden knowledge of them being soulmates. Kind of a "your husband died of a massive coronary, Mrs. Walker, but I also found a fungus growing in the depths of his big toe nail". The thought makes her nose wrinkle, as she sets Sherlock's coffee next to his work on the slab. She's stopped holding the cup out to him since that day.

He barely notices and Molly has a worry he might turn and accidentally knock the drink over, so she reaches out again if only to pull the cup a little farther from his still arm. When she looks up, she's taken aback by his focus on her; he's studying her again. He does that every once in a while, usually on her date nights when she's tried something new with her appearance. This time, she stares at him back, instead of turning away with a flush like she always does.

He's tired. God, is he tired. This case that Detective Lestrade's given to him must be big, because he'd gone back and forth to her lab to examine the body a good five or six times this week. Molly kind of wishes she hadn't bought him the coffee; what he needs now is rest. If Sherlock hadn't been so stubborn, she'd bet her recent promotion he'd keel over and collapse right about now.

"Sherlock?" she asks, hesitantly, and then she notices that he's staring at her hands, which is when she realizes it. It doesn't take long for her to decide, even if she had sworn to herself early on it would never happen again. Oh, but Sherlock bloody Holmes was probably playing on a see-saw of pros and cons in his head right about now, and Molly knows she had to make the first move before the bloody idiot actually does fall over.

"Sit."

He narrows his eyes at her.

"Sit and give me your hand."

Surprisingly, he obliges, but the movement of his outstretched arm shows reluctance and Molly can't help but roll her eyes. She pulls up another stool for herself before holding his one, large hand with both of hers.

Molly suppresses the joy her body feels at their contact, even if it's all her cells could think of. She could tell Sherlock's trying to do the same, doing his best impression of the most stoic statue she's ever seen.

"My parents were soulmates," Molly starts and she can see an ounce of immediate fear in Sherlock's eyes. It's so painfully obvious that he hates the idea, either of the concept of soulmates or of Molly herself. Either way, her stomach knots itself and she feels nauseated with disappointment along with the high. She remains holding onto his hand tight.

"They married immediately after. It's so rare, you know? Finding soulmates. You hear about all these magical stories, and you think that's what will happen if you find yours," Molly continues. "I know my parents loved each other, I know they did. They had my brothers and I very soon after their wedding, but I think they never got to get to know each other. They were so caught up in their supposed fairy tale ending that they didn't realize it wasn't working." She pauses.

"Mum's remarried now. Ed makes her very happy, happier than I had seen her when she was with my father and he…" She could feel the corner of her lips fall. Her brows pinch together at the thought. "Dad died alone. I mean, my brothers and I were there, but…" When she looks up at him, she's glad he's still watching her. There had been a twinge of fear running through her body that he had gone back to examining body parts rather than listening to her.

"I don't particularly care if we're soulmates, you know. I don't really believe in that, even if it does exist. I don't think two people will end up together just because of this," she nudges both of their hands. "So if you ever need a boost, whether it's coffee or this, I—"

Molly doesn't say anything after that. He _must_ know how obvious her feelings for him are, soulmates aside. She just wants him to know that she cares in spite of all that.

When he nods with a slight vigor that shows he's not about to fall asleep on the spot, a brief _thank you_ uttered from his lips, Molly smiles and breathes a breath she hadn't known she was holding.

* * *

Sherlock Holmes is an arse, Molly concludes one afternoon. A childish arse.

Since having met John Watson, his willingness to hold her hands during work had disappeared. At first, she felt insulted at the idea that Sherlock Holmes would be ashamed of being soulmates with her, but it was after her rant one afternoon that he stops her and tells her he doesn't care who knows. She could announce it to the papers —though he really doesn't think it's wise for her sake, and she agrees—and he wouldn't care. Rather, he's testing John's level of perception.

Molly merely shakes her head and moves back to her work, just moments before John shows up to talk to Sherlock about the most recent murder. She doesn't think anything of this game, until he starts demanding more coffee, and instead of letting her place it on the desk, he goes out of his way to reach out for it, making sure their fingers overlap during the exchange.

The number of energy bursts running through her body each time she sees the detective-doctor duo is enough to keep her awake for forty-eight hour shifts, if she tried, and considering what it's doing to _her_, she doesn't even think Sherlock needs the coffee.

He occasionally stops to stare at her, sometimes pushing a strand of hair away from her face, as John gawks at them, before saying something distasteful about her new look, even if she's done nothing out of the ordinary that particular day. John raises an eyebrow, but doesn't say anything after the insult, so Sherlock continues.

If Sherlock's an arse, then John is an idiot.

"I'm telling you, Sherlock, I still don't see anything," John says next to Molly, peering through the microscope that Molly had laid out for them as per Sherlock's request.

The detective rolls his eyes, and deep down, Molly thinks she should be moving away, but dammit, she had been sitting there first before the pair had strolled into her lab. She doesn't want to have to move all of her equipment for whatever concoction Sherlock had planned.

He walks over in large strides, pushing John away as he looks deep into the microscope again. His long fingers curled gently around the coarse and fine objective knobs, slowly spinning and refocusing his image.

Molly's eyes trail down to where his pinky touches the side of her hand. It runs up and down slowly, as if soothing her from another burst of rage.

"John, get me the results from yesterday's tests. I need to make a comparison."

"I'm not your servant, you dolt," John replies, but turns around to find the papers anyway and Molly wonders how Sherlock has all of them bidding his commands.

In that moment, the pinky that had been touching Molly's hand turns into his entire hand overlapping hers. Their fingers entwined, Sherlock momentarily looks up from the lenses, if only to smirk at her gentle blush surfacing at her cheekbones.

By the time John comes back, only Sherlock's pinky is touching Molly. John doesn't even notice.

* * *

"Preposterous, I don't even know why I'm here," Sherlock whines for what seems to be the eighth time that night.

"Oh, shut it, Sherlock. You deserve this!" Greg yells back.

Molly rolls her eyes, sipping on her Coke. She thinks if Sherlock really wants to, he could have left by now, but John must be rubbing off on him, because despite leaning back on his chair and paying no attention to the cheers and clinking glasses of the police squad, the detective remains in his seat.

It had been quite a large case, which is why Greg had pushed for the idea for all of them to go out to the pub nearby. Sherlock insisted on sitting as far away from Philip and Sally as possible, opting to sit across from Molly instead. Molly laughs out loud when he says that, but it hurts a little that, if given the chance, he wouldn't sit near her at all.

The topics the group talks about roll by easily, with occasional input from her and Sherlock. She makes small talk with Sally, glad that their friendship is blossoming somewhat. Molly doesn't have too many work friends being secluded in the morgue so often; sometimes she likes that about her job, sometimes it feels lonely.

"So Molly," John says, "I hear you've met someone new?"

At the question, everyone stops chattering to look at her, and Molly could feel her face flush in embarrassment. Out of all of them, she feels Sherlock's piercing stare the most.

"U-Um, yes. His name's Jim and he—"

Before she says anything, a wave of energy over takes her system and she could feel every part of her skin rising into bumps. Below the table, Sherlock's foot rests against the inside of her calf.

"Molly? You alright there?" Greg suddenly asks, and Molly's eyes widen. She does a quick nod and forces her head in an angle that creates a crick in her neck, but prevents her from seeing Sherlock's face. She feels his ankle bone underneath his trousers, rubbing small circles along her calf now, enough to pull away the tiredness she had been feeling earlier.

"Yes, sorry. Where was I? Um, he's new at Bart's and works in the IT department." Sherlock's other foot toes with hers, and Molly's tempted to yell at the man-child to stop distracting her, but then she thinks about Jim and how sweet he was to her the other day, and smiles in spite of the distraction by her feet. "We met while I was getting Sherlock some coffee the other day."

Molly tries not to notice when Sherlock's feet retract from hers, and it doesn't take too much effort. Sally and Greg tease and pester her for more details, and John raises his glass to which she clinks with her own. By the time she's turned to look at Sherlock, he's already gone.

* * *

The night before Sherlock leaves for his however many years long mission, Molly finds out her head fits quite comfortably in the crook of his neck. Any other time, she would revel in the fact that Sherlock hasn't let go of his arms around her, but at that moment, she's in an internal struggle between the calm and soothing sensation radiating off of Sherlock's body to hers, and the anxious, dwelling thought that this may be the very last time she sees him.

She hasn't asked him what happened on that rooftop and Sherlock doesn't say. All she remembers after Mycroft announcing their success was Sherlock entering her apartment and struggling to ask her if it was okay. She didn't have to ask him what that meant either, she just nodded. They've been lying together on her bed since.

Molly remembers, as she rubs small circles on Sherlock's arm, how her parents used to do this after a big fight. They would just sit on the couch together, breathing in and out like it was all they could do, holding onto each other to calm the other person down. She idly wonders if that's the reason why they divorced, if they had been too dependent on each other as soulmates to really solve their problems as husband and wife.

"Stop thinking so loud," Sherlock murmurs into her hair, but Molly feels his smile anyway.

"'M sorry," she sighs and can't help but smile when he holds her closer.

"I might not be coming back, you know."

She remembers the day the coffee spilt between them and seeing Sherlock walk pass her without a care. In spite of the lump constricting her throat, she whispers, "I know."

"It might be for the best," he continues, to which she wants to scream in retaliation. "I'm afraid I've gotten quite dependent on this...experiment of ours."

Molly digs her face deeper into the buttons of his shirt. Even now, his words still hurt.

"Who knows, you might find..._someone_ that one might say is compatible with you. No one like Jim, of course," he jokes. It's the first time one of them has mentioned Moriarty since the incident, and if Molly hadn't been in Sherlock's calming arms, she presumes an awful chill would have gone down her spine.

She doesn't say anything right away, even if she wants to tell him the thought itself is so impossible, because she's so terribly in love with him, but she knows he knows. It's why he's telling her to move on.

Finally, she says, "You'll have to go back to cheap coffee, once that happens. John will be annoyed because you'll be grumpy in the mornings and won't have your wake-up call."

"Hm, I suppose I could start smoking again."

Molly smacks him on the shoulder and Sherlock lets out a quiet laugh that rumbles down his chest and echoes in her heart.

When Sherlock leaves the next day, the tips of his fingers leaving hers, Molly cries her way to his fake funeral, feeling the withdrawal settling in.

* * *

Sherlock and Molly don't touch each other again when he comes back, not initially. It takes all the strength Molly could muster not to run up to him into a giant hug, desperate for the whole-body experience of goose bumps again, a feeling that now only sits in her memories late at night when she wonders how he is. She knows he notices, but he doesn't comment, at least, not until sometime later, when he congratulates her on her engagement.

She thanks him, but can't help but feel that it's all wrong. She knows she loves Tom, is sure of it. He may not be as brilliant as Sherlock, but he has never once insulted her and at the face of every problem, he makes sure to communicate it clearly with her so they could both solve it without a fight in tow. Molly has made it very clear she cares for feelings over the concept of soulmates, and yet she cannot help but feel a gush of air running down her throat to the pit of her stomach, sitting there until she's sick, every time she feels disappointed there's no spark when she touches Tom.

"Molly?"

She looks up, at Sherlock's soul-searching eyes focusing on hers. "May I?"

"May you what?" She asks. It's a broken whisper.

"One last time?"

She loves Tom, but she thinks this is necessary. With a slight nod, Sherlock bends down and she closes her eyes. He presses his lips on the side of hers, enough so that the spark she's been missing for the past three years comes back tenfold, bringing her memories with it

Before she could sink in it, Sherlock steps back and leaves.

* * *

She and Tom have an awful row in the midst of their wedding planning, not even calmly talking it through helps. She heads straight to the morgue while he goes out with his buddies, both intent on calming themselves down separately. To her lack of surprise, Sherlock is already there with John and Mary, all circling around a cadaver like some strange cult, all the while talking about John and Mary's own wedding plans.

It's Mary, God bless her woman's intuition, who comes over to Molly's desk first, and asks her if she wants to talk about whatever it was that was troubling her, in a quiet voice to keep the men behind them from eavesdropping, thankfully.

Molly just shrugs. "Wedding stress, I suppose."

Mary nods understandably, palms her hand over Molly's, and wishes Molly the best.

"It'll work out, Molly," Mary says, and Molly knows she's talking about her and Tom, but can't help but flicker her attention to the detective in the back. When she refocuses back to Mary, a slight bout of panic at the tip of her tongue, Mary's lips are parted in an _ah!_

With that, the blonde slides off of Molly's desk, she nods at Molly once. "You'll be okay," she says before heading back to the men and the corpse.

Molly diverts back to her notes, but just as quickly as Mary had arrived to her desk, she hears Mary shout out, "We'll be heading off now" to the room. John looks awfully confused, but seems to be willing to be dragged away from Sherlock by Mary anyhow, and Molly secretly wonders what the blonde promised him in return.

The pathologist could _feel_ the tension in the air by the time it's only her and Sherlock in the morgue, especially when his footsteps become louder. He stands in front of her desk, studying her like he always does.

"He hurt you," he says.

Molly frowns. "No, he didn't."

"Not physically, but he hurt you," Sherlock points out and Molly's reminded of his annoying need to always be right. "He insulted you."

She slams her pen on her desk, foregoing her work and finally staring at Sherlock straight in the eye. "We had a row. We said things we didn't mean. It's _fine_, Sherlock."

"No, you're not. You're clearly upset. You're not satisfied with the way things are turning out between your engagement with T…" He squints at the thought, eventually deciding to stop bothering Tom's name. "You're upset because the man you thought wouldn't be able to hurt you was capable of doing so in a matter of less than five words. You—"

"_Sherlock_," Molly half yells, half begs, and for a moment, she's scared she'll start crying and won't be able to stop, but then she hears a screech, and the next thing she notices is Sherlock dragging a stool next to her. He sits on it and takes her hand with both of his. It pulls the tears away from the corners of her eyes.

"I'll be fine, Sherlock," Molly tells him. She can feel her heart rate slow down to normal and the memory flashes of her fight with Tom almost disappears in her mind. "I'm used to being insulted anyway. You do it all the time." She doesn't know why she says the last part, because she hates how guilty he suddenly looks. His fingers around her hand tightens, and he manages to look at her without it appearing like he's trying to analyze her like one of his experiments.

"I apologize, Molly," he says slowly and carefully. It's all he says without the need for reiteration.

Molly finds that even though the source of her anger had not been because of him, his words and continuous presence with his thumb circling along the palm of her hands is enough to make her feel a little better. She's practically feeling like herself by the time he suddenly scrambles off the stool, stepping a little too quickly to his work again.

Molly looks at him with a confused daze, just moments before Tom enters the lab with a bouquet of flowers in his hands and an apology at his lips.

* * *

She kisses Sherlock in his flat a week and a half after she and Tom end their engagement, had marched straight to 221B, tugged onto his scarf without a care that he was likely on his way to meet up with John and Mary, and pressed her lips on his.

Molly thinks that regardless of that euphoria, that high, that's supposed to be there whenever they so much as brush their pinky fingers, that the rush of excitement going through her system is supposed to happen anyway, because there's something between her and this man, that's much more than some dumb evolutionary mutation. And she thinks Sherlock knows that too, because he kisses her with just as much want as she does, and holds her body close like that night after Moriarty.

There's this fear that had been running through her mind for a while, that one day Sherlock might have to leave again and this time, he might not come back. She tells him this through the tips of her fingers, raking through the curls of his hair and the nape of his neck. He understands her fully but he'll try his best not to, he tells her, when he pulls her closer with the hand on the small of her back.

It isn't until she hears someone clear their throat that Molly forces herself to separate from Sherlock, even if he doesn't want to. His head remains slightly bowed down to her level, unwilling to withdraw into a straight posture. He looks positively annoyed. Molly, on the other hand, steps back and finds John with his expressive, questioning brows and a gleeful, very pregnant Mary behind Sherlock.

"Shall we leave you two alone?" John asks, teasing. It makes the blood rush to Molly's face even quicker and Sherlock grunts in annoyance.

"N-No. Sorry, I didn't—" Molly stammers, but Mary waves her off.

"Would you like to have dinner with us, Molly? I'm sure Sherlock would like the additional company," Mary says with a wide, devilish grin.

Molly's eyes widen, her thought processes from earlier that day hadn't reached this far in her planning. She turns to Sherlock who looks at her adoringly, and even with the lack of contact, she feels a burst of energy streaming through her body.

On their way to dinner, Sherlock takes hold of Molly's hand, and doesn't let go.


End file.
